The present invention relates to a portable apparatus for ventilation support to persons with respiratory distress, with a compressed air pump which may be connected to the mouth of the nose via tube means for generation of pressure pulses with an individually adaptable air volume, which pump comprises a rigid container consisting of two symmetrical halves and with a flexible membrane which is located as a laterally reciprocating diaphragm between the two container halves, that are provided with check valves permitting ambient air to be fed into the pump and from the pump into the tube means while the membrane wall is moved, for generation of a pressure pulse.
Prior art in the field of breathing aids, comprises portable units and non-portable units that, if required, may be moved inside a hospital or be used within an ambulance, but may not be comfortably carried when travelling, thereby fulfilling the criteria of being classed as portable. For example, apparatuses are available that provide oscillatory pulse types, IPPV, which apparatuses are heavy and expensive.
Conventional breathing aids for the above described area of use, often comprise a fan which creates a static overpressure, which is aimed to open and to ventilate the respiratory system of the user. However, this method, CPAP (Continuous Positive Air Pressure) lead to other drawbacks as noise, desiccation of the respiratory system and a high consumption of energy. Also, this method only works if the brain controls the diaphragm.
It is also known to use a piston or accordion pump for providing pressure pulses. However, these pump units are more bulky than fans and are normally combined with comparatively complicated electronics for synchronisation of the pump function to the user breathing rhythm. Accordingly, also these apparatuses have become energy demanding as well as expensive and unwieldy.
So far, membrane pumps have particularly been used on stationary apparatuses for spray painting, because they are normally very space consuming in comparison with fans and piston or accordion pumps.
Normally, the air requirement during sleep for the age of 18-80 years is about 7 liters per minute, for example the equivalent to 1 respiration of 0.6 liter every fifth second, while small children may respire about 30 times per minute with a corresponding smaller tidal volume. Accordingly, a breathing apparatus must have a relative wide capacity for adjustment, in order to cover occurring needs. This is difficult to achieve for single-action pumps.
Therefore the object of the present invention is to provide a space-saving and simple apparatus which solves or at least reduces the above described problems.
For this object, the invention is characterized in that the pump is provided with flexible pull means for reciprocating operation of the membrane in the container, said pull means extending via pulley wheels to a driving device located substantially in the same plane as the container and beside it. Because of this configuration of the invention, it is possible to use an efficient operating and power saving double action membrane pump.
Advantageous embodiments of the invention are disclosed by the accompanying claims.